PT-2026-41147 · Pypi · Mistune
CVSS v3.1
6.1
Medium
| Vector | AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Name of the Vulnerable Software and Affected Versions
mistune (affected versions not specified)
Description
The Image directive plugin fails to properly validate the
:width: and :height: options. The validation uses a regular expression that only checks if the value starts with a digit, rather than ensuring the entire string is a valid number. When a value is not a plain integer, it is inserted directly into a style attribute without escaping.This allows an attacker to inject arbitrary CSS properties by providing a value that begins with digits followed by malicious CSS. For example, using the
:width: parameter, an attacker can inject properties such as position:fixed, background-color, and z-index to create a full-page phishing overlay or perform UI redressing attacks, effectively covering the entire browser viewport and concealing legitimate page content.Recommendations
At the moment, there is no information about a newer version that contains a fix for this vulnerability.
Exploit
XSS
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Weakness Enumeration
Related Identifiers
Affected Products
Mistune